Filler for projectiles



Patented Mar. 8, I932 yum'rE HARRY J. NICHOLS, OF WASHINGTON, DISTRICT 01 COLUMBIA FILLER FOR PROJECTILES 1T0 Drawing.

This invention relates. to improvements in explosive shell-fillers for armor piercing projectiles, and has for one of its objects the production of an explosive adapted to the filling of projectiles compacted under high'pressure into the projectile will remain permanently friable, elastic and semi-plastic.

Another object of. the invention is the pro duction of an explosive shell-filler composition which may be loaded into projectiles with facility and safety under high pressure and which will after compression e extremely insensitive to shock or frictional detonation and i5 defiagration while its explosive ingredient normally is so sensitive.

A further object is to provide an explosive which is non-hygroscopic and which will not be subject to chemical change or deterioration during long storage periods.

It has heretofore been the universal practice in the loading. of armor piercing projectiles either to cast the shell-filler solidly into the projectile or to compress it therein with such pressure as to insure that it will not subsequently set u or be further compressed by the shock o firing or impact. It

is known that the sensitiveness of an explosive to shock is increased by making it more compact and ri id, which localizes the effects of impact. owever, heretofore the necessity of avoiding the creation of friction between the explosive and the walls of the projectile due to the movement of the explosive on firing or impact with armor is so great that the shell-filler hasnevertheless been unsafely compressed into the projectiles at reat pressures in order to insure rigidity of the shell-filler. after'loading. In addi- 40 tion to the devices of casting and compression, various provisions such as the addition of binders like paraiiin, resin, less sensitive explosives, etc., and also paper or fabric cartons or coverings have been employed in an effort to decrease the sensitiveness and to secure additional rigidity of the shell-filler.

The provisions just mentioned have practically eliminated the danger of premature xplosion due to the shock or firing the projectile in the gun, and to a certain extent have Application filed April 22,

which when compressed or sions have projectile causing frictional im 1924. Serial ms. 708,106.

reduced the tendency of the shell-filler to explode prematurely from the shock incident to penetration of armor at normal angles of impact. However, with the comparatively recent requirement that armor piercing projectiles be capable of penetratlng armor at oblique angles of impact, the above provibeen found to be inadequate for the reason that when penetrating armor at oblique angles, the projectile itself is deformed by the excessive forces'to which it is subjected, and no matter how rigid or densely compacted the shell-filler maybe, it also is violently deformed in the same manner as the act of the explosive filling with the interlor wall of the projectile as well as between the particles of the thus disrupted explosive filling resulting heretofore in its premature detonation and deflagration since the stress arising from said deformation substantially supplements that due to impact with the armor. It is therefore manifest that the difliculties presented are'not to be solved simply by securing higher density and greater rigidity of the shell-filler, but its solution requires the devising of a high explosive shell-filler composition of the detonating class which is substantially insensitive to detonation and defiagration by the combined impacts with the armor and of deformation in piercing such armor, but substantially preserve its sensitivity to detonation by the usual detonating means.

A further obstacle against extending the present methods of shell-filling is that the risks attendant to the loading operations are increased with an increase in the loading pressure. Also larger and more powerful loading presses are required and the final result here tofore has been a rigid mass of explosive which is correspondingly more difiicult to detonate as well as more sensitive to detonation by the combined impacts with the armor and of deformation in piercing such armor at an angle.

It is known that the sensitiveness of explosives to impact may be decreased by mixing them with a soft, plastic substance which will reduce the friction. between particles and decrease the efiect of shocks to which the explosive may be subjected, such as mixing therewith materials such as parafin, resin, gums, balsams and gelatines, which substantially decrease the sensitiveness of the explosive constituent to detonation by the detonating means. When applied to shell-fillers to meet the aforesaid armor piercing diliiculties now being experienced these materials, however, possess the disadvanta e that by their use the particles of the shellller are cemented together, so that when the resulting rigid mass is violently deformed during penetration of armor, the particles or crystals of explosive are crushed or broken tending to produce pre mature explosion. I

To meet the diiliculties recited above I have discovered that any of the aromatic nitro class of explosives in crystalline form may be employed as a shell-filler and composition which may be compressed into the projectile at very high pressure with practical safety till and facility and yet remain premanently friable, elastic and semi-plastic, and which will therefore adapt itself readily and without excessive or deflagrating or detonating friction due to the extreme stresses of impact of its containing projectile with armor as well as to the changes in the form of the projectilewhich occur to the greatest extent during the penetration of armor at an angle, thereby reducing the danger of premature explosion.

Heretofore, the high explosives of the detonating class, particularly the picrates and the trinitrotoluene groups, upon detonatlon produce fumes that may be permanently harmful especially in such usually enclosed.

quarters as require the piercing of armor to enter, and my composition armor piercing projectile filler substantially relieves the permanency of said harmful characteristics pf either or both of its said explosive constituents.

To accomplish these objects and results and to obtain the most desirable characteristics of the shell-filler from every standpoint, in the invention herein disclosed the granules or crystals of explosive are coated with a firmly adhering, elastic, powdered lubricant, such as a-stearate, and an excess of lubricant is provided to till interstices and to separate the individual particles, said stearate being ground finer than the explosive. The explosire after being so treated may be safely compressed underhigh pressure into the pro ectile body by hydraulic pressure or other suitable means.

The class of aromatic nitro-explosi 'es comprises tetrauitro-methylaniline, hexauitro-diphe'nylamine, trinitro-benzene, trinitrotoluene, ammonium pit-rate, sodium picrate, trinitro-dimethylaniline, trinitrocrcsol, and picric acid. ()1? the constituents of this class ll have successfully employed trinitrotoluene and ammonium picrate, and from the same beneficial results are attainable with substantially like admixture with the other constituents of said class.

For the purpose of my invention I have found that zinc stearate as a lubricant and cushioning material hasevery desired quallty. Zlnc stearate possesses the'.peculiar quality of adhering readily to other materials without havingany tendency for the particles of the zinc stearatc itself to stick together. The particles of explosive when coated with zinc steal-ate therefore have a high degree of mobility. which, in connection with the elastic cushioning properties of the Z1110 stearate, renders the explosive mixture, even after high compression, friable, elastic and semi-plastic. I have found that 2 to 5% of zinc stearate mixed with an explosive, such as trinitrotoluene orammonium picrate, gives a composition of desirable chemical and mechanical characteristics differing substantially from those of either or both of its said explosive constituents and of maximum density for a given pressure. When using this, percentage of zinc stearate there is no loss of sensitivity to detonation by the usual timing detonating means with substantially no diminution of its explosive force since, because of the lubricating qualities of the zinc stearate, the actual amount of'explosive material which may be charged into the projectile at a given pressure is greater than when the explosive is used without thezinc stearate and the safe pressure to which my composition may be subjected is greatly increased over that of its constituent explosive, and l have safely used pressures as high as fifteen thousand (15,000) pounds per square inch with my composition. From the standpoint of friability, elasticity and plasticity, however, it may be desirable to incadmium stearate and aluminum stearate,

but I prefer to use zinc stearate for economic reasons.

It is known that trinitrotoluene and ammonium picrate in their crystalline form are especially adapted for cl'iarging shells because 01? their relative chemical stability, durability, insensitivity and great explosive power. In carrying out my invention I therefore add to a crystalline or granular explosive, preferably trinitrotoluene or ammo nium picrate, a suitable amount of zinc stearate, which is mixed therewith in a suitable mixing machine until the particles of explosive are coated with an adhering layer of zinc stcarate and the mixture is thoroughly blended. The mixture is then compressed into the projectile in the usual manner. When compressed at pressures as great as 15,000 pounds per square inch, which is safely applicable to my composition of zinc steal-ate and trinitrotoluene or ammonium picrate, my said composition remains permanently friable, elastic and semi-plastic.

My said composition of zinc stearate and,

said trinitrotoluene or ammonium picrate, in substantially the proportions named, substantially retards the normal sensitiveness to (leflagration and to detonation by impact of said explosive constituents such that without said stearate admixture either of said explosives have heretofore usually been detonated as well as deflagrated by the combined stresses of impact with armor at such an angle that the projectile is substantiall deformed, whereas with said admixture of either of said explosives with said stearate results in such an armor piercing shell-filler composition that its projectile container ma pierce armor at a substantial angle and be sn stantially deformed thereby without liability to detonation or deflagration by the potent combined forces of impact with armor and of such deformity of the projectile and its content as is usually occasioned by piercing armor at an angle, and my said composition may usually be relied upon to detonate only by its detonating means ordinarily set to detonate the shell-filler a given distance within the ves sel or fortification whose armor its container has penetrated, where the normal toxic or other permanent harmful effects, upon the occupants of such usually enclosed quarters protected with said armor, of the gas arising from said detonated explosive constituent when used and detonated alone, are, by said stearate content of my said composition modified so as to relieve said permanent effects.

On a ialysis, the process of pressing said granular or crystalline explosives to obtain a particular density of my compositionbecomes simply the safe application of suflicient mechanical power to force the particles into such positions and density of the mass that the interstices between theni are reduced. In so doing, some of the granules or crystals are broken and others are forced into such positions that they present an elastic resistance to further compression. It will therefore be apparent that the use of such a lubricant facilitates the safe pressing of such crystalline or granular explosives and in fact, when using zinc stearate as such lubricant, a marked improvement in the safety and facility of loading has been obtained in practice, in addition to thereby changing the normal characteristics of its explosive constituent so that the sensitivenesss of my composition to detonation by the usual detonatin g means remains substantially the same as that of its explosive constituent alone; while the sensitiveness of my composition to detonation. as well as to deflagration, by said combined forces of impact upon armor and of such deformation as is occasioned by the piercing of armor at an angle is so stabilized-that it is not detonated or deflagrated thereby, while either of its explosive constituents are detonated'as well as deflagrated usually thereby. and that the detonated gas of my composition is normally not permanently harmful in the usually enclosed space where said detonation is designed to occur, while said gas of either of its explosive constituents may be so harmful in such space. While this substantiallychanges the characteristics of such explosives to detonation as well as deflagration by the combined forces of shell impact and distortion due to piercing relatively heavy armor at a substantial angle, the normal sensitiveness of such explosives to detonation by the usual timing means provided therefor remains substantially unchanged.

A further advantage in the use of zinc stearate is that it is insoluble in water or alcohol and is not easily Wetted and therefore,

after the explosive particles are coated with it, the shell filler is rendered less hygroscopic and in storage is not liable to deteriorate nor to form dangerous compounds which are very unstable and sensitive to detonation, and heretofore were formed by the reaction of either of said explosive constituents when used alone, upon the interior surface of the projectile, but which reaction and its said effect are prevented in my composition.

From the above it will be seen that my invention provides an explosive shell-filler for filling armor piercing projectiles which after compression is friable, elastic and semi-plastic; which gives a high density of loading; which is extremely insensitive to shock or friction; which is non-hygroscopic and not liable to chemical change. or deterioration; and which is loaded with safety and facility. It therefore possesses in a high degree the qualities requisite for the uses for which it is intended.

My invention, however, is not restricted to the use of zinc stearate, since other stearates, palmitates, oleates, resinates or other forms of metallic soaps I have found suitable for carrying out the objects of my invention. It is therefore to be understood that various changes may be made in the proportions and constituents of the explosive shell-filler without departing from the scope of the invention as defined in the appended claims.

What I claim is 1. A shell filler comprising a mixture of ammonium picrate and a zinc soap.

comprising a mixture of an aromatic nitrocomprising a mixture of an aromatic nitroexplosive and a zinc soap.

6. A filler for armor piercing pro ectiles explosive and a zinc soap, each in crystalline form, said soap being substantially 2.5 to 15 percent of the mass.

7. A shell filler comprising a mixture of an aromatic nitro-explosive and a metallic stearate, the latter being substantially 2.5 to 15 percent of the mass.

8. A shell filler comprising a mixture of an aromatic nitro-explosive in crystalline form and a metallic stearate.

9. A shell filler comprising a mixture of an aromatic nitro-explosive and a zinc stearate.

10. A shell filler comprising a mixture of an aromatic nitro-explosive in crystalline,

form and a zinc stearate.

11. The method of rendering an explosive normally sensitive to detonation insensitive to deonation by impact, substantially commensurate with that of a containing shell impacting with and penetrating substantial armor at an angle, consisting of mixing with an aromatic nitro-explosive a metallic soap.

12. The method of decreasing the sensitiveness to detonation by impact of an explosive normally sensitive thereto; consisting of mixing with an aromatic nitro-explosive a metallic soap. I

13. The method of rendering an explosive normally sensitive to detonation insensitive to detonation by impact, up to the degree commensurate with that of a containing shell impacting with and penetrating substantial armor at an angle, consisting of mixing with an aromatic nitro-explosive a metallic soap in different proportions of from substantially 2.5 to 15 percent of the mass.

14. The method of decreasing by different degrees the sensitiveness of an explosive normally sensitive thereto, consisting of mixing with an aromatic nitro-explosive a metallic soap in difierent proportions of from substantially 2.5 to 15 percent of the mass.

15. The method of decreasing the sensitiveness to detonation by impact of an explosive normally sensitive thereto, consisting of mixing with an aromatic nitro-explosive a metallic soap each in the form of dry particles.

16. The method of decreasing the sensitiveness to detonation by impact of an explosive normally sensitive thereto, consisting of mixing with said explosive a metallic soap each in the form of dry particles with said soap particles being substantially powdered, and forming substantially from 2.5 to 15 percent of the mass. r

17 The method of rendering an explosive normally sensitive to detonation insensitive to detonation byimpact, substantially-commensurate with that of a containing shell impacting with and penetrating substantial armor at an angle, consisting of separatelyreducing an aromatic nitro-explosive and a metallic soap to the form of dry particles and intimately mixing said particles, with said soap being from substantially 2.5 to.15 percent ofthe mass.

'18. The method of rendering an explosive normally sensitive to detonation insensitive to detonation by impact, substantially commensurate with that of a containing shell impa'cting with and piercing substantial armor at an angle, consisting of separately reducing a trinitrotoluene explosive and a metallic soap to the form of dry particles with said soap particles being relatively finer and intimately mixing said particles, with said soap being from substantially 2.5 to 15 percent of the mass. 1

19. The method of decreasing the sensitiveness to detonation by impact of an explosivenormally sensitive thereto, conslstmg of mixing a trinitrotoluene explosive and a metallic soap each in the form of dry particles and compressing under high pressure portions of the mass into the volumes and forms in which said mixture is desired to be exploded.

20. The method of decreasing the sensitiven'ess to detonation by impact without substantially changing its normal characteristics of detonation by the usual detonating means, consisting of mixing an explosive and a metallic soap, the latter being substantially 2.5

to 15 percent of the mass.

- 21. The method of decreasing the sensitiveness to detonation by impact without substantially changing its characteristics of detonation by the usual ,detonating means, consist ing of mixing a trinitrotolu-ene explosive and a metallic soap, the latter being substantially 2.5 to. 15 percent of the mass.

22. The method of decreasing the sensitiveness to detonation by impact without sub-- stantially changing its' characteristics of detonation by the usual detonating means. consisting of mixing ammonium picrate and a metallic soap.

23. The method of decreasing the sensitiveness to detonation by impact without substantially changing its characteristics of detonation by the usual detonating means, consisting of mixing ammonium picrate and metallic soap each in the form of dry particles.

24. The method of decreasing the sensitiveness to defia 'ration of an explosive normally sensitive thereto, consisting of mixing an aromatic nitro-explosive with a metallic soa 2%. The method of rendering the detonated gases of an explosive of the shell-filler class less harmful to the occupants of closures wherein shells so filled'may explode, consisting of mixing with an aromatic nitro-expl0- sive zinc stearate.

26. The method of rendering an explosive normally sensitive to detonation insensitive to detonation by impact, substantially commensurate with that of a containing shell impacting with and piercin armor at a. substantial angle, consisting o separately reducing ammomum picrate explosive and a metallic soap to the form of dry particles with said soap particles being relatively finer and intimately mixing said particles with said soap being substantially25 to 15 percent of the mass. I

27. The method of decreasin the sensitiveness to detonation by impact 0 an explosive, consisting of mixing ammonium picrate ex-. plosive and a metallic soap each in the form of dry particles and compressing under high pressure portions of the mass into the volumes and forms in which said mixture is desired to be exploded.

28. The method of decreasing the sensitiveness to detonation by impact without substantially changing its characteristics of detonat-ionby the usual detonating means, consisting of mixing an ammonium picrate explosive and a metallic soap, the latter being substantially 2.5 to 15 percent of the mass.

Signed at Washingslon, District of Colum bia, this 29th day of arch, 1924.

HARRY J. NICHOLS. 

